title: Regulation of aromatic amino acid biosynthesis in Escherichia coli K-12: control of the aroF-tyrA operon in the absence of repression control.
abstract: Evidence was found which indicated that a mutation in gene trpS affected the rate of synthesis of tyrosine-repressible 3-deoxy-D-arabinoheptulosonic acid-7-phosphate (DAHP) synthetase. The effect was found to occur independently of repression mediated by the tyrR gene product, and it was not due to a change in growth rate, nor was it a manifestation of the stringent response. It is proposed that in the proximal region of the aroF-tyrA operon there is an attenuator site controlled by the level of charged tryptophanyl-transfer RNA. In addition, it was demonstrated that starvation for certain amino acids led to degradation of tyrosine-repressible DAHP synthetase, but not phenylalanine-repressible DAHP synthetase, and supplementation with the missing amino acid led to an increased rate of synthesis of tyrosine-repressible DAHP synthetase during subsequent growth.
mesh_terms: D000596:Amino Acids / Q000096:biosynthesis*; D004794:Enzyme Repression / Q000187:drug effects; D004926:Escherichia coli / Q000235:genetics*; D001277:GTP Pyrophosphokinase / Q000235:genetics; D007661:Ketoses / Q000235:genetics*; D009876:Operon; D010649:Phenylalanine / Q000494:pharmacology; D013403:Sugar Phosphates / Q000235:genetics*; D014364:Tryptophan / Q000096:biosynthesis / Q000235:genetics; D014443:Tyrosine / Q000096:biosynthesis / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D007661:Ketoses; D013403:Sugar Phosphates; C013469:3-deoxy-D-arabino-heptulosonate-7-phosphate; D014443:Tyrosine; D010649:Phenylalanine; D014364:Tryptophan; D001277:GTP Pyrophosphokinase